I am printing Rhino PDF from a layout, replacing a previous file of same name. The original file is not open in any other program. Nothing should prevent the file overwrite as far as I know.
This would be my area since I wrote the Rhino PDF exporter.
I haven’t seen this one before. Mitch, does this happen with any file you try to overwrite when generating a PDF? Here’s a wild guess, is there a Rhino that is “stuck” and hidden in the background (check task manager).